ALS offers a variety of methods and applications for pesticide and herbicide analysis.

It is well known that the analysis of organochlorine pesticides by traditional EPA methodologies that use Gas Chromatographs with Electron Capture Detectors (GC/ECD) are often affected by the presence of PCB congeners (polychlorinated biphenyl congeners) and other co-extractable interferences causing false positive identification and/or over estimation. High biased results for organochlorine pesticides can lead to an overall lack of data confidence and unnecessary environmental actions.

Pesticide SprayerTo eliminate co-extractable and PCB congener interference, ALS has developed a unique method using isotope dilution with Large Volume Injection (LVI) and GC/MS/MS. Using standard extraction procedures combined with this analytical method, ALS is able to achieve detection levels up to 20 times lower than typically observed by ECD detection.

The triple-quad LVI/GC/MS/MS provides excellent selectivity in complex matrices by generating unique spectral fingerprints. These fingerprints provide unambiguous identification producing increased data defensibility. This enhancement is essential in further reducing co-extractable interferences. Isotopic standards increase the precision and accuracy in measuring the concentration of the pesticides. This method is applicable to water, soil/sediment and tissue matrices.

PESTICIDES IN AIR OR SURFACE

Assessing personal exposures to pesticides indoors or out of doors may be complex due to the existence of thousands of pesticides.

ALS offers panels of various pesticide categories to assist screening and quantitation in air and on surfaces at very low levels:

Organophosphorous pesticides panel

Organochlorine pesticides panel

Chlorinated organonitrogen pesticides panel

Acid herbicides pesticides panel

Home and office pesticides control panel I

Home and office pesticides control panel II

Carbamate insecticides panel

Plant leaf/Surface residues

Pesticide metabolites in urine

Broad GC/MS pesticide screen

EPA soil and water methods for pesticides also available

QUANTERNARY AMMONIUM HERBICIDES IN WATER

ALS can provide analytical testing for quaternary ammonium herbicides in water with reporting limits of less than 5ng/l. On the basis of their toxicity, the World Health Organization (WHO) has classified diquat and paraquat as moderately hazardous and considered as priority pollutants, chlormequat and mepiquat are classified as slightly hazardous.

Due to this, there is concern about the presence of these compounds in different matrices such as fruits, soils and waters. In response to this issue, ALS has developed, validated and accredited a method capable of analysing these compounds in water at ultra-trace levels using state of the art instrumentation.